Field of the Invention
The present invention relates to a method for operating a switching system for data packets having inputs and outputs, with temporary storage of the data packets at the input. Such switching systems for data packets are used, by way of example, for the design of local data networks (LAN=Local Area Network). An example of such a local data network is known by the name “ETHERNET” as a technical standard.
In such data networks, it is necessary for the data to be routed from a source to a destination in the form of data packets. This requires an appropriate switching system. On the basis of the prior art, the only solution there was for such switching systems for data packets in networks was either for the data packets to be temporarily stored at the input (INPUT BUFFERED) or for the data to be temporarily stored at the output (OUTPUT BUFFERED). Both solutions based on the prior art have considerable disadvantages. When the data packets are temporarily stored at the input, the system can be blocked by so-called “HEAD-OF-LINE BLOCKING”. In addition, traffic control by allocating different priorities to different data packets, and hence preferential switching of particular, especially urgent data packets, is possible only with great difficulty.
In the case of temporary storage at the output, a very large bandwidth is required for the buffer at the output, and such a system with temporary storage at the output additionally requires a very rapid decision about the data path to be used (routing).
Systems having a common memory, which represent a combination of a buffer at the input and a buffer at the output, also require a high bandwidth for the memory.
To date, the only switching systems on the market with a high bandwidth are those with temporary storage at the output, for example from Texas Instruments, or very complicated systems having a common memory.